Hong Kong Officials Threaten British Activist With National Security Law

HONG KONG—A London-based group that campaigns for human rights in Hong Kong said national security officials from the Chinese city have threatened its leader with imprisonment and demanded it take down its website, a sign the city is extending its battle with critics globally.

Hong Kong Watch on Monday shared a letter addressed to its co-founder and chief executive Benedict Rogers that said that its activities—such as lobbying other countries to impose sanctions on China or the city—are jeopardizing China’s national security and that offenders could be sentenced to at least three years or up to life in jail.